Handle packaging barcodes and improve weighing logic

Added logic in InputQty.cs to prevent quantity modification if the SN is a packaging barcode, setting an error message and status. Updated MES_WIP_PKG table during production. Moved CurPkg initialization in Weighing.cs from constructor to TryBegin method, and added a waiting message in the constructor. TryBegin now initializes CurPkg with relevant data if it doesn't exist.